Is it safe to keep Ryzen 1600 on stock (auto) voltage and frequency?

I tried to overclock my Ryzen 1600 to 3.6 Ghz with 1.25V. Test went good. My PC didn't freeze or anything, but I've noticed that I have short (0,5 seconds) freezes while watching movies, youtube or gaming with sharp buzzes from speakers. I decided to go back to stock settings leaving Voltages, Frequency on auto with default turbo boost (up to 3.6 as it goes with Ryzen 1600) but I see that the Voltages jumps like mad from 1.1 up to 1.406 in HWMonitor. It's very anoing and I'm constantly affraid that something is wrong with my CPU...

Do Ryzen 1600 should tweak voltages this way or it's a problem with my motherboard (which is MSI B350M Pro-VDH btw)?